Absorbent article having a front urine-collecting part and a rear faeces-collecting part

ABSTRACT

An absorbent article such as a diaper, an incontinence guard or the like in which the top sheet (1) of the article includes a transverse barrier (11) which divides the article into a rear and a front part (4, 6) and which is intended to prevent faeces discharged to the rear part of the top sheet from moving to the front part thereof. Arranged in the absorbent body (3) essentially opposite the top sheet barrier (11) is a liquid barrier (21) which prevents, either completely or partially, the transportation of liquid in the absorbent body from the front part of the article to the rear part thereof, at least in the layer (18) of the absorbent body that lies proximal to the wearer in use.

TECHNICAL FIELD

The present invention relates to an absorbent article, such as a diaper,pants-type diaper, an incontinence guard or like article which includesa liquid-permeable top sheet, a liquid-impermeable bottom sheet and anabsorbent body disposed therebetween, wherein the top sheet includes atransverse barrier which divides the article into a front and a rearpart and which is intended to prevent faeces discharged to the rear partof the article moving to the front part thereof.

BACKGROUND OF THE INVENTION

It is known to provide the top sheets of diapers with transversebarriers for the purpose of preventing faeces from spreading to thefront part of the diaper. EP-A-0,355,740 teaches such transversebarriers, which are created either by fastening strings of plastic foamto the top sheet or by creating transverse folds or pleats with the aidof elastic devices which extend in the longitudinal direction of thediaper in the crotch region thereof and therewith gather the top sheettogether in this region. WO 94/14395 also teaches a corresponding typeof transverse barrier in the outer sheet material.

The transverse barriers are intended to prevent faeces discharged to therear part of the diaper spreading forwards in the diaper and dirtyingthe wearer's skin and genitals. The barriers also prevent urine andfaeces mixing together on the diaper surface, since it is a known factthat the skin is much more sensitive to a mixture of urine and faecesthan to each of the two components per se. Faeces contain certainenzymes which are believed to constitute an important factor inirritation of the skin. Urine is also liable to produce ammonia in thepresence of faeces, therewith increasing the Ph, which in turn increasesthe enzymatic activity of said enzymes.

However, such transverse barriers are unable to prevent urine fromspreading to the rear parts of the diaper via the underlying absorbentbody and there being mixed with faeces, resulting in the aforesaiddegradation products which are liable to cause skin irritation problems.

THE OBJECT OF THE INVENTION AND ITS MOST SIGNIFICANT CHARACTERISTICFEATURES

The object of the present invention is to provide an absorbent article,such as a diaper or an incontinence guard, with which urine and faecesare kept separate most effectively both on the top sheet and in theunderlying absorbent body. This object has been achieved by providing inthe absorbent body at a position essentially opposite the top sheetbarrier a liquid barrier which prevents transportation of liquid in theabsorbent body from the front part of the article to its rear part,either completely or partially and at least in those upper parts of theabsorbent body that lie proximal to the wearer.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will now be described in more detail with reference toexemplifying embodiments thereof and also with reference to theaccompanying drawings.

FIG. 1 is a view of a diaper from above, as seen from the side that liesproximal to the wearer.

FIG. 2 is a corresponding view from above of another embodiment of adiaper.

FIG. 3 is a schematic longitudinal section view of the diaper shown inFIG. 2.

FIGS. 4 and 5 are respective schematic longitudinal section views of anabsorbent body according to two embodiments.

DESCRIPTION OF EMBODIMENTS

The diaper illustrated in FIG. 1 indicates a liquid-permeable casingsheet 1, made for instance from nonwoven or perforated plastic film, aliquid-impermeable casing sheet 2, made for instance from plastic filmor hydrophobic nonwoven fabric, and an absorbent body 3 which isenclosed between the two casing sheets 1 and 2.

The diaper is intended to be worn around the lower part of the wearer'strunk as a pair of absorbent pants. The diaper has a rear part 4 which,in use, lies rearwardly of the wearer, a front part which, in use,extends forwardly of the wearer, and a narrower crotch part 6 which islocated between the rear part 4 and the front part 5 and which isintended to be placed in the wearer's crotch between the wearer'sthighs. To enable the diaper to be fastened in the desired pants-likeform, fastener tapes 7 are provided in the proximity of the rear waistedge 8 of the diaper. In use, the fastener tapes or tabs 7 are fastenedto the outer surface of the front diaper part 5, close to the frontwaist edge 9, such as to hold the diaper together around the wearer'swaist. Naturally, other fastening devices, such as Velcro® fasteners,hooks and eyes, etc. are conceivable.

The diaper illustrated in FIG. 1 also includes pre-tensioned elasticdevices 10, which may be comprised of any suitable material, such aselastic foam, elastic ribbons, bands or covered elastic threads. For thesake of simplicity, the elastic devices have been shown in a stretchedstate in FIG. 1. However, immediately the stretch in the elastic devicesis relaxed, the devices will contract and therewith form elastic edgesaround the leg openings of the diaper.

It will be understood that the illustrated diaper is merely anon-limiting exemplifying embodiment. For example, the shape of thediaper and its construction in general may be varied. For instance, inthe case of diapers that are intended to be supported within specialtightly-fitting pants, the fastener devices, i.e. the fastener tapes 7,can be omitted, and possibly also the elastic devices 10. The fasteningdevices are also omitted in so-called pant diapers or training pants.

A transverse barrier 11 is provided in the crotch region of the diaperand extends generally transversely to the longitudinal direction of thediaper. The barrier has an upward extension (height) towards the wearerand is intended to prevent faeces spreading from the rear diaper part 4to the front diaper part 5, and to prevent urine spreading along the topsheet 1 from said front part to said rear part.

The top sheet barrier 11 may extend transversely across the diaper in astraight or a curved line and may be constructed in a known manner and,for instance, consist in a fold formation in the top sheet or inseparate strips of material mounted on the top sheet, such as strips ofplastic foam or strips or nonwoven, which may optionally be providedwith an elastic device along the outer free edge so as to impart alifting effect to the strip.

The embodiment illustrated in FIGS. 2 and 3 corresponds to the subjectof Swedish Patent Application 9400916-4 and has a casing sheet thatincludes an inner casing sheet 1a and an outer top sheet 1b on that sideof the absorbent body 3 which lies proximal to the wearer in use, i.e.the inner casing sheet 1a lies proximal to the absorbent body 3 and theouter top sheet 1b lies proximal to the wearer in use. The outer topsheet 1b may either be comprised of liquid-permeable orliquid-impervious skin-friendly material. This diaper is also providedwith leg elastic 10.

The top sheet includes two openings 12 and 13 which are elongated in thelongitudinal direction of the diaper. That region 14 of the outer topsheet 1b which lies between the openings 12 and 13 is located betweenthe faeces discharge point and the wetting point, i.e. those regions ofthe diaper in which faeces and urine are delivered thereto when thediaper is positioned correctly.

Two elastic threads 15, 16 are fastened in a stretched state to theouter top sheet 1b and extend from the front diaper part to the reardiaper part along the side edges of the openings 12 and 13 in the mannerdescribed in more detail in Swedish Patent Application 9400916-4.

A tubular body 17 is mounted in a flattened state in the top sheetregion 14, between the top sheet 1b and the inner casing sheet 1a, andextends transversely between the points of attachment of the top sheet1b to the bottom sheet 2 and the inner casing sheet 1a. The top andbottom sides of the tubular body 17 are fastened respectively to the topsheet 1b and the inner casing sheet 1a with the aid of a glue bead, byultrasonic welding or by like means, for instance.

The tubular body 17 may be comprised of a liquid-permeable orliquid-impermeable material and is preferably made of the same materialas the bottom sheet, the inner casing sheet or the top sheet. Instead ofusing a tubular body 17, the barrier between the openings 12, 13 mayalternatively be comprised of a single wall of flexible material whichis mounted in a folded state between the inner casing sheet and the topsheet and fastened to said sheets in a manner corresponding to thefastening of the tubular body 17.

The barrier may alternatively be formed by pleats or folds produced inthe inner casing sheet or in the top sheet, as also described in SwedishPatent Application 9400916-4.

Generally opposite the barrier 11 and 17 respectively, there is providedin the absorbent body 3 a liquid barrier which prevents liquid spreadingfrom the upper sheet of the absorbent body from its front to its rearpart, either completely or to a substantial extent.

The embodiments illustrated in FIGS. 4 and 5 include an absorbent body 3which comprises three different sheets or layers, an upper acquisitionlayer 18, an intermediate storage layer 19 and a bottomliquid-dispersion layer 20. The acquisition layer 18 is convenientlycomprised of an absorbent material having a relatively large pore size,high wet resilience and low liquid-dispersion ability, such asmechanical cellulose fluff pulp, thermomechanical orchemithermomechanical cellulose fluff pulp (CTMP), chemically stiffenedcellulose fibres, synthetic fibres, absorbent foam material, etc.

The major part of the absorbent material in the storage layer 19 iscomprised of fluff pulp or some other fibre material of relatively smallpore volume and high liquid-dispersion capacity. Chemically producedfluff pulps, which are comprised of fine fibres of essentially purecellulose, generally have a high liquid-dispersion ability. Fluff pulp,for instance CTMP pulp, compressed to a density greater than about 0.12g/cm³, also has a relatively good liquid-dispersion ability. Anothermaterial which exhibits good liquid-dispersion properties is compresseddry-formed sheet pulp of, e.g., CTMP, or chemical pulp. Such material isdescribed in WO 89/00605. Absorbent foam materials may also be used.

The fibre material in the dispersion layer will preferably comprisemostly of chemical fluff pulp, dry-formed sheet pulp in accordance withthe above, or of some other fibre material that has good dispersionproperties.

The acquisition layer and the storage layer may include a certain amountof superabsorbent, whereas the dispersion layer is preferably free fromsuperabsorbent or contains only very small quantities of superabsorbent.

In the embodiments illustrated in FIGS. 4 and 5, the front part 18a ofthe acquisition layer 18 is thinner than the rear part 18b thereof. Inthe FIG. 4 embodiment, this increase in thickness takes place in asingle step, whereas in the FIG. 5 embodiment the thickness of theacquisition layer increases successively from a region that liesimmediately behind the anticipated wetting point of the diaper. Thethinner front part 18a ha a high density than the thicker rear part 18b.The higher density of the thinner front part 18a is obtainedautomatically when compressing the absorbent body, due to the reversedthickness relationship of the underlying storage layer 19, provided thatthis layer has a higher compression resistance than the acquisitionlayer 18. The compression resistance of a fluff pulp body depends on thetype of pulp concerned and the amount of superabsorbent containedtherein, among other things.

As a result of the higher density of the front part 18a, said front partwill have a smaller mean pore size than the rear part 18b. Since thecapillary force increases with decreasing pore sizes, the liquiddischarged to the front part of the receiving layer 18a will not spreadto the rear part 18b to any great extent, but will be transportedimmediately into the underlying storage layer 19. The rear part 18b ofthe acquisition layer will thereby remain mostly dry.

As illustrated in FIGS. 4 and 5, a mechanical liquid barrier 21 may beprovided as a complement to the difference in pore size, e.g. in theform of a plastic strip or a strip of some other liquid-impervious orhydrophobic material provided in the acquisition layer 18, between thefront and the rear parts 18a and 18b. Such a mechanical liquid barrier21 will prevent liquid leaking to the rear part 18b of the receivinglayer should the front part 18a be temporarily saturated. The liquidbarrier 21 may be separate from or integral with the barrier 11 or 17 inthe top sheet.

When a mechanical liquid barrier 21 is used in the acquisition layer 18,there is no need for the differences in pore size between the front andthe rear parts 18a and 18b in order to prevent the transportation ofliquid between said parts. However, an advantage is gained when the rearpart 18b includes a material having a relatively large pore size inorder to prevent rewetting from the underlying storage layer 19.Furthermore, an advantage is gained when the rear part 18b is able toabsorb loose faeces effectively.

As before mentioned, the difference in pore size between the front andthe rear parts 18a and 18b of the acquisition layer can be obtained bydifferences in the density between said parts, although a difference inpore size can also be obtained with one and the same density by usingdifferent types of fibre material in the different parts. Polymericfoams of varying pore sizes can also be used in addition to fibre-basedabsorbent materials.

A liquid barrier can also be provided in the acquisition layer 18, bycompressing a stripe in the material.

The liquid barrier will preferably not extend through the full thicknessof the absorbent body, but will preferably be restricted to its uppersheet or layer. This will enable liquid to still spread in the bottomlayer of the absorbent body, i.e. in the storage and the dispersionlayer. It is important that the upper surface of the absorbent bodyproximal to the wearer is kept dry.

By providing in the top sheet a barrier which prevents faeces fromspreading from the rear diaper part to its front part, and by providingin the upper layer of the absorbent body a liquid barrier which preventsliquid from spreading in said layer from the front to the rear partthereof as proposed in accordance with the invention, urine and faecesare separated highly effectively in the diaper, therewith preventing theformation of certain skin-irritating degradation products which areotherwise formed when urine and faeces mix.

Another advantage that can be obtained by keeping the upper layer of theabsorbent body dry in the rear part of the diaper is that this willenable different types of top sheet to be used in the front and in therear part of the diaper respectively. For instance, a conventionalcasing material can be chosen for the front part, this materialisolating the skin from the liquid in the absorbent body, while choosinga hydrophilic absorbent casing material for the rear part, this materialbeing suitable for absorbing loose faeces, for instance fabric ornonwoven comprised of rayon, cotton or other hydrophilic natural fibres.

The invention is, of course, not restricted to the illustratedembodiments thereof since a number of variants are conceivable withinthe scope of the following claims.

What is claimed is:
 1. An absorbent article comprising:aliquid-permeable top sheet, a liquid-impermeable bottom sheet, and anabsorbent body enclosed therebetween, the top sheet includes atransverse barrier which divides the article into a front part and arear part and which is intended to prevent faeces delivered to the rearpart from moving to the front part, the absorbent body includes a liquidbarrier which is located essentially opposite the first-mentionedbarrier in the top sheet and which prevents, either completely orpartially, the transportation of liquid in the absorbent body from thefront part of the article to the rear part thereof, at least in theupper parts of the absorbent body that lie proximal to the wearer,wherein the liquid barrier is located inside the absorbent body and theliquid barrier does not extend completely through the absorbent body butonly extends in the upper parts of the absorbent body that lie proximalto the wearer.
 2. The absorbent article according to claim 1, whereinsaid liquid barrier is produced by virtue of a difference in mean poresize in the absorbent material, such that at least in the upper layer ofthe absorbent body proximal to the wearer, liquid is prevented bycapillary action from spreading, either totally or partially, from thefront part of the layer to its rear part, at least provided that thefront part is not saturated with liquid.
 3. The absorbent articleaccording to claim 2, wherein the absorbent body includes a first layeradjacent the top sheet and a second layer adjacent the bottom sheet, andthe liquid barrier extends completely through the first layer and doesnot extend into the second layer.
 4. The absorbent article according toclaim 1, wherein said liquid barrier includes a strip ofliquid-impervious maternal, which is either separate from or integralwith the top sheet barrier.
 5. The absorbent article according to claim4, wherein the absorbent body includes a first layer adjacent the topsheet and a second layer adjacent the bottom sheet, and the liquidbarrier extends completely through the first layer and does not extendinto the second layer.
 6. The absorbent article according to claim 1,wherein the liquid barrier includes a strip of hydrophobic materialwhich is either separate from or integral with the top sheet barrier. 7.The absorbent article according to claim 6, wherein the absorbent bodyincludes a first layer adjacent the top sheet and a second layeradjacent the bottom sheet, and the liquid barrier extends completelythrough the first layer and does not extend into the second layer. 8.The absorbent article according to claim 1, wherein said liquid barrierincludes a compression stripe in the absorbent material.
 9. Theabsorbent article according to claim 8, wherein the absorbent bodyincludes a first layer adjacent the top sheet and a second layeradjacent the bottom sheet, and the liquid barrier extends completelythrough the first layer and does not extend into the second layer. 10.The absorbent article according to claim 1, wherein the absorbent bodyincludes an acquisition layer which lies proximal to the wearer, and oneor more underlying storage and dispersion layers wherein said liquidbarrier extends essentially only through the acquisition layer.
 11. Theabsorbent article according to claim 10, wherein the front part of theacquisition layer has a higher density than the rear part of said layer.12. The absorbent article according to claim 11, wherein the density ofthe rear part of the acquisition layer decreases successively in arearward direction.
 13. The absorbent article according to claim 12,wherein the absorbent body includes a first layer adjacent the top sheetand a second layer adjacent the bottom sheet, and the liquid barrierextends completely through the first layer and does not extend into thesecond layer.
 14. The absorbent article according to claim 10, whereinthe front and the rear parts of the acquisition layer include differenttypes of absorbent structures having different pore sizes.
 15. Theabsorbent article according to claim 14, wherein the absorbent bodyincludes a first layer adjacent the top sheet and a second layeradjacent the bottom sheet, and the liquid barrier extends completelythrough the first layer and does not extend into the second layer. 16.The absorbent article according to claim 1, wherein the liquid-permeabletop sheet that lies proximal to the wearer in use is comprised ofmutually different kinds of material in the front part and the rear partof the article respectively, wherein the rear part of the top sheet iscomprised of a hydrophilic material suitable for absorbing loose faeces,e.g. fabric or nonwoven comprised of rayon, cotton or some otherhydrophilic natural fibre, whereas the front part of the top sheet isconstructed to insulate the wearer's skin from the liquid absorbed inthe absorbent body.
 17. The absorbent article according to claim 16,wherein the absorbent body includes a first layer adjacent the top sheetand a second layer adjacent the bottom sheet, and the liquid barrierextends completely through the first layer and does not extend into thesecond layer.
 18. The absorbent article according to claim 1, whereinthe liquid barrier divides a first part of the absorbent body from asecond part of the absorbent body.
 19. The absorbent article accordingto claim 18, wherein the absorbent body includes a first layer adjacentthe top sheet and a second layer adjacent the bottom sheet, and theliquid barrier extends completely through the first layer and does notextend into the second layer.
 20. The absorbent article according toclaim 1, wherein the absorbent body includes a first layer adjacent thetop sheet and a second layer adjacent the bottom sheet, and the liquidbarrier extends completely through the first layer and does not extendinto the second layer.
 21. The absorbent article according to claim 1,wherein the absorbent article is a diaper.
 22. The absorbent articleaccording to claim 1, wherein the absorbent article is a pant diaper.23. The absorbent article according to claim 1, wherein the absorbentarticle is an incontinence guard.